Rotatable access door



Jan. 31, 1956 J. E. HOGAN ET AL ROTATABLEI ACCESS DOOR Filed Nov. 24, 1952 United States Patent() ROTATABLE ACCESS DOOR John Edward Hogan and Lloyd R. Poe, Los Angeles, Calif., assignors to Clark Hartwell and Eleanor M. Hartwell, both of Los Angeles, Calif., copartners, doing business as Hartwell Aviation Supply Company, Los Angeles, Calif.

Application November 24, 1952, Serial No. 322,296

2 Claims. (Cl. 220-40) Our invention relates to rotatable access doors and included in the objects of our invention are: First, to provide a rotatable access door which, when closed, is flush with the surrounding surface and, therefore, particularly useful on aircraft for the purpose of providing inspection openings.

Second, to provide a rotatable access door wherein opposed latch elements engage under cooperating margins of the opening and are so arranged that the door is cammed or lifted out of and free of the door margins as the door is rotated toward its open position.

Third, to provide an access door which is particularly economical of manufacture and easy to install.

With the above and other objects in view as may appear hereinafter, reference is directed to the drawings, in which:

Figure 1 is an outside view of our access door showing fragmentarily the surrounding member in which it is mounted.

Figure 2 is a back or inside view of our access door.

Figure 3 is a front view of the door frame with the door member removed but indicates by broken lines the movement of the door as it approaches its open position.

Figure 4 is a sectional view through 4-4 of Figure 3.

Figure 5 is a sectional view through 5-5 of Figure 3.

Figure 6 is a rear or inside view of the door member separated from its frame.

Figure 7 is a transverse sectional view thereof through 7 7 of Figure 6.

Our access door includes a door frame 1 shown as formed from a circular piece of sheet material and having cut or stamped therein a substantially oval shaped door opening 2. At the ends of the opening there are formed substantially tangential notches 3. The two longer sides of the oval opening form keeper margins 4, one keeper margin adjacent its notch 3 having a cam element 5 formed by bending inwardly or rearwardly a corner of the margin confronting the notch. The other margin is provided adjacent its notch with a stop lug 6 formed by cutting a radial slit in the margin adjacentthe notch and bending the intervening portion inwardly or rearwardly. Near the extremities of the margins 4, remote from their respective cam element and stop lug, the margins are provided with inwardly projecting Vrudimentary retainer ribs 7.

The door frame is adapted to be secured on the inner or back side of a sheet metal body A in which has been formed a circular opening B. The door frame is secured by rivets or other fastening means associated with its peripheral portion.

It should be observed that the door frame may be integral with the body A by providing in the body a door opening 2 arranged as described hereinbefore and recessing an area corresponding to the circular opening B. A door member 8 is provided which is circular so as to conform to the opening B.

Secured to the back side of the door member is a latch .2,732,970 Patented Jan. 31, 1956 plate 9 having a central portion 10 welded or otherwise secured to the door member. The latch plate is provided with diametrally opposed latch arms 11 which are bent inwardly or rearwardly from the door member and then bent so that their extremities converge toward the door member as best shown in Figure 7. The side margins of the latch arms are foldedas indicated by 12 so that the extremities of the latch arms are essentially channel shaped in cross section. The door member is provided with a slot 13 adapted to receive a screw driver or similar tool. The slot is covered by the central portion of the latch plate. This portion may have a vrecess 14 so as to increase the effective depth of the slot 13.

Our rotatable access door is operated as follows:

When the door member is in its closed position, shown in Figures 1 and 2, the latch armsll underlie the keeper margins 4 between the retainer ribs 7 and the cam element 5 and stop lug 6, respectively. In ord er to open the door, the door is rotated clockwise as viewed in Figure 2 (counterclockwise as viewed in Figure l). On rotation of the door the latch arms 11 ride over the retainer ribs 7 and into the end regions of the oval opening 2. The latch arms clear the ends of the opening so that the door is free. However, it frequently happens grease or other material having adhesive properties may cause the door to stick in place and inasmuch as the door'is flush or without external handle means, it is sometimes difficult to raise the door from its opening. Should this be Vthe case, continued rotation of the door in a clockwise direction as viewed in Figure 2 causes one of the latch arms to cam across the cam element 5, raising the corresponding margin of the door. At the same time the opposite latch arm engages the shoulder formed under the stop lug 6, causing the door to pivot about the extremity of this latch arm and swing the door out of the door opening. This latter movement is indicated by broken lines in Figure 3. The direction of rotation as viewed inthis gure is counterclockwise.

The retainer ribs 7 prevent accidental opening of the door and the stop lug 6 prevents over-travel when the door is turned to its closed position.

Having fully described our invention, it is to be understood that we do not wish to be limited to the details herein set forth, but our invention is of the full scope of the appended claims.

We claim:

1. A rotatable access door, comprising: a frame plate having a door opening of greater length than width, keeper margins disposed along opposite sides of said opening and each notched at one extremity to form lateral clearance spaces at the ends of said opening, said margins being deformed to provide opposed retainer ribs; a door member adapted to cover said opening; a latch plate secured to said door and including oppositely directed yieldable latch arms arranged to pass through said opening when said latch plate is disposed endwise in said opening, said latch arms adapted on rotation of said door and latch plate to engage said keeper margins and ride over said retainer ribs; one of said keeper margins adjacent said notch being shaped to form a cam operable to engage said keeper in a manner to force said door away from said frame to facilitate opening of the door; the other of said keeper margins being provided adjacent its notch with a stop means to limit closing movement of said door and also operable to form a fulcrum point in cooperation with said cam to facilitate opening of said door.

2. A rotatable access door, comprising: a frame plate having a door opening of greater length than width, keeper margins disposed along opposite sides of said opening and each notched at one extremity to form lateral clearance spaces at the ends of said openings, said margins being deformed to provide opposed retainer ribs; means defining a circular aperture centered relative to said door opening and of larger area to expose the margins of said frame plate bordering said door opening; a circular flat door member adapted to t said aperture ush with the surface ofsaid means and in contact with said frame plate; a latchplate secured to said door and including oppositely directed yeldable latch arms arranged to pass through said opening when said latch plate is disposed endwise in said opening, said latch arms adapted on rotation of said door and latch plate to engage said keeper margins and ride over said retainer ribs; one of said keeper margins adjacent said notch being shaped to form a cam operable to engage said keeper in a manner to force said door away from said frame to facilitate opening of the door; the other of said keeper margins being provided adjacent its notch with a stop means to limit closing movement of said door and also operable to form a fulcum point in cooperation with said cam to facilitate opening of said door.

References Cited in the lile of this patent UNITED STATES PATENTS 

